With constant progress in technological fields, various kinds of electronic products have been developed to provide people with more convenience and comfort in their daily life. In these electronic products, memory integrated circuits play a very important role. The currently available memory integrated circuits may be generally divided into two types, namely, volatile memory and non-volatile memory, according to their data storage characteristics.
The non-volatile memory can retain the stored data even when no power is supplied thereto, and has been widely applied in memory cards and USB flash drives. Since consumers demand for memory having higher access speed and accuracy but lower power consumption, it has now become an important issue as how to develop a memory with increased data access speed and accuracy to satisfy the market demands. Presently, the most frequently discussed issue is the large voltage or current offset in a current-sense amplifier. The offset of voltage or current would adversely affect the quality of a circuit system. In a current-sense amplifier for memory, inputting of offset current or voltage would cause unstable detection accuracy to thereby reduce the memory data read speed and accordingly, result in incorrect data reading.
Please refer to FIG. 1 that is a schematic circuit diagram of a conventional current-sense amplifier. As shown, the conventional current-sense amplifier often has asymmetrically arranged transistors in a differential current mirror. As a result, cell current ICELL and reference current IREF input to the sense amplifier for comparison are not ideal, which in turn forms a hindrance in increasing memory data read speed and accuracy. It is therefore tried by the inventor to work out a way for effectively reducing the current offset of the differential current mirror in order to enable increased memory data access speed and accuracy.